The Microscopic Germ Theory of Disease. By H. C. Bastian. 135 
therein — facts which would seem to point to the conclusion, or at 
least are quite consistent with the notion, that the contagious 
poison may be a chemical compound which gradually becomes 
destroyed or modified by the successive changes taking place in 
association with processes of putrefaction. 
4. There is the extreme improbability of the supposition that 
this whole class of diseases should be caused by organisms known 
only by their effects. 
5. The fact of the sudden cessation, periodical visitations, and 
many of the other phenomena of epidemics, however difficult they 
may be to explain upon any hypothesis, seem to oppose almost 
insuperable obstacles to the belief that living organisms are the 
causes of such epidemics of specific contagious diseases. 
It would seem little better than an ill-timed attempt at jesting 
to postulate the existence of distinct germs for these several specific 
fevers, and at the same time to endow such imaginary entities with 
properties different from those of all known germs. To remain 
always in the germ stage in media favourable for their multipli- 
cation would, even if the imaginary germs were visible, be contra- 
dictory to all previous experience ; but to suppose, in addition, 
that such hypothetical invisible entities are capable of resisting the 
influence of agencies which have been proved to be destructive of 
all known living matter would seem to be going altogether beyond 
the bounds of probability. And if we look at the question from 
this point of view, we may regard it as a definitely established fact 
that the virus of cholera, for instance, is not composed of living 
germs or particles. Messrs. Lewis and Cunningham have shown* 
that the virus is not appreciably impaired in activity when the 
fluids containing it have been raised for a few minutes to a tempe- 
rature of 212° F. ; and in reference to this subject they say, “ We 
have seen no living object preserve its vitality after exposure in a 
fluid to a temperature approaching to 212° F., nor have we been 
able to satisfy ourselves that anyone else has done so. 
In only one of the specific fevers commonly met with in the 
human subject have organisms been found in the blood : this 
exception is relapsing fever. There is, however, an affection occa- 
sionally communicated from cattle (sang de rete, or splenic fever) 
in which organisms are also met with in the same situation. But 
the fact of the existence of actual visible organisms in these cases 
seems altogether robbed of its significance after the occurrence of 
archebiosis and heterogenesis in diseased fluid and tissues has been 
demonstrated. The view, indeed, that the organisms found in 
these affections owe their origin to certain changes prone at times 
* ‘ Report, &c., into the Nature of the Agent or Agents producing Cholera,’ 
pp. 46 and 57, 1874. 
YOL. XIY. 
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